670
FXUS63 KDTX 160945
AFDDTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI
445 AM EST TUE DEC 16 2025
KEY MESSAGES
- A WARMUP IS FORECAST FOR THE MIDDLE OF THE WEEK WITH TEMPERATURES
IN THE MID TO UPPER 30S WEDNESDAY AND 40S ON THURSDAY.
- A STRONG STORM SYSTEM IS FORECAST TO IMPACT THE GREAT LAKES REGION
LATE THIS WEEK. MUCH OF THE PRECIPITATION IS EXPECTED TO FALL IN
THE FORM OF RAIN ON THURSDAY, TRANSITIONING TO SNOW IN SOME AREAS
FRIDAY. GUSTY WINDS WILL ACCOMPANY THIS SYSTEM.
- THERE IS THE POTENTIAL FOR ANY MOISTURE ON ROADWAYS TO FLASH
FREEZE THURSDAY EVENING/NIGHT AS ARCTIC AIR MOVES BACK INTO THE
REGION.
AVIATION
STEEPING LOW LEVEL INVERSION KEEPING LOW CLOUDS (LOW MVFR) TRAPPED
FOR NOW, BUT SHOULD SEE A SOUTH TO NORTH CLEARING TREND THIS MORNING
AS FURTHER WARM AND DRY AIR STREAMS IN FROM THE SOUTHWEST. SOUTHWEST
LOW LEVEL JET INCREASING TO 50 KNOTS AROUND 2KFT TOWARD EARLY
EVENING. DAYTIME MIXING SHOULD ALLOW FOR SURFACE WINDS TO TAP INTO
SOME OF THE HIGHER WIND SPEEDS, WITH WIND GUSTS AROUND 25 KNOTS
EXPECTED. SOUTHWEST WINDS STAY ELEVATED THIS EVENING AND TONIGHT
(ABOVE 10 KNOTS) BUT LIKELY LOSE THE GUSTINESS OR BECOME MORE
SPORADIC. UNIDIRECTIONAL FLOW FROM THE SURFACE TO 2KFT PREVENTS THE
MENTION OF LLWS IN TAF, NOT MEETING TRUE CRITERIA.
SURFACE MOISTURE ADVECTION TONIGHT AS SURFACE DEW PTS CLIMB ABOVE 30
DEGREES. THIS SHOULD ALLOW FOR RENEWED DEVELOPMENT OF LOW MVFR
CLOUDS UNDERNEATH STRONG INVERSION AROUND 2KFT. THE START TIME IS
MORE IN QUESTION, AND COULD BE ANYTIME BETWEEN 3-7Z, WITH HIGH
CONFIDENCE AFTER 7Z AS SURFACE WINDS ALSO BEGIN TO TREND WESTERLY
FOR WEDNESDAY MORNING.
DTW THRESHOLD PROBABILITIES...
* LOW FOR CIGS AOB 5000 FEET THIS MORNING, HIGH TONIGHT.
PREV DISCUSSION
ISSUED AT 337 AM EST TUE DEC 16 2025
DISCUSSION...
THE ESTABLISHMENT OF LOW AMPLITUDE, WEAK UPPER LEVEL RIDGING OVER
NORTH AMERICA WILL LEAD TO RELATIVELY QUIET WEATHER TODAY THROUGH
EARLY THURSDAY. STOUT WARM ADVECTION IS PROGGED DURING THE NEXT 6-12
HRS WITH H5 HEIGHTS INCREASING 10 DAM AND 850MB TEMPERATURES RISING
SOME 6-10 DEGREES C. THE NET RESULT WILL BE EXTREME STATIC STABILITY
THIS MORNING BETWEEN 1.0 AND 10.0 KFT AGL. CLOUD TRENDS WILL BE
HIGHLY DEPENDENT ON WHETHER OR NOT THE BLANKET OF LAKE MICHIGAN
STRATOCUMULUS WILL LIFT NORTHWARD/OR ERODE AS WINDS TRY TO TURN
SOUTHWESTERLY AND STABILITY ATTEMPTS TO LOWER IN THE COLUMN. TOUGH
CLOUD FORECAST WITH THE NAM ALREADY SIGNIFICANTLY UNDERRESOLVING THE
AMOUNT OF LOW CLOUD OVER LOWER MICHIGAN. DO THINK ITS GOING TO TAKE
AWHILE, BUT SHOULD SEE SOME SUNSHINE UP INTO METRO DETROIT THIS
AFTERNOON. FOR THE LATE AFTERNOON AND EARLY EVENING, MODELS CONTINUE
TO SUGGEST THAT WEAK SHORTWAVE ENERGY WILL STREAM ACROSS LOWER
MICHIGAN AS WARM AIR ADVECTION CENTERS ON NORTHERN LOWER MICHIGAN AND
IN VICINITY OF SAGINAW BAY. AT THE SAME TIME, THE SOUTHERN EDGE OF
LOW LEVEL JET ENTRANCE REGION WILL IMPINGE SOUTHWARD ON THE NORTHERN
CWA. FORECAST DATA HAS EXHIBITED A FAIRLY PERSISTENT SIGNAL THAT WEAK
LIFT WILL HAVE THE POTENTIAL TO GENERATE SOME LIGHT QPF ACROSS
PORTIONS OF NORTHERN LOWER MICHIGAN IN THE 21-03Z TIMEFRAME. THOUGHT
ABOUT ADDING A SLIGHT CHANCE FOR SOME FREEZING DRIZZLE IN THE TRI
CITIES AND NORTHERN THUMB, BUT FORECAST SOUNDINGS KEEP THE LOWEST
7.0-8.0 KFT AGL SUBSATURATED AND VERY DRY. COULD SEE SOME LARGER
DROP SPRINKLES SURVIVE DOWN TO THE SURFACE, BUT THE THOUGHT IS THAT
THE DURATION WILL BE EXTREMELY SHORT. DECIDED TO KEEP THE FORECAST
DRY.
A WEAK COLD FRONT IS FORECASTED TO SETTLE SOUTHWARD PUSHING INTO THE
FAR SOUTHERN CWA INCLUDING METRO DETROIT BETWEEN 09-12Z WEDNESDAY
MORNING. CONCURRENTLY, MOISTURE ORIGINATING OUT OF TN/KY IS EXPECTED
TO LIFT NORTHEASTWARD STREAMING OUT AHEAD OF THE FEATURE. THE
CONTROL RUNS OF THE EMCWF HAVE BEEN GENERATING SOME LIGHT QPF ACROSS
METRO DETROIT THAT WOULD LIKELY BE IN THE FORM OF DRIZZLE OR
FREEZING DRIZZLE (AIR TEMPERATURES AT OR ABOVE FREEZING, WITH
SURFACES LIKELY BELOW). SOMETHING TO MONITOR, BUT MUCH OF THE
REMAINING MODEL GUIDANCE IS VERY BEARISH ON THE IDEA. PROBABLY WILL
BE VERY ISOLATED AND INCONSEQUENTIAL WITH INVERSION HEIGHTS AT A
VERY LOW SUB 2.0 KFT AGL. DAYTIME HIGHS WEDNESDAY ARE EXPECTED TO BE
IN THE UPPER 30S TO AROUND 40 DEGREES.
VERY GOOD MODEL CONTINUITY IN ADVANCING DEEP TROUGH AND COHERENT
VORTICITY MAXIMUM ACROSS THE NORTHERN PLAINS WEDNESDAY. THE
DOWNSTREAM RESPONSE WILL BE THE DEVELOPMENT OF STRONG MERIDIONAL
MOISTURE TRANSPORT THAT ARRIVES OVER THE AREA AFTER 12Z THURSDAY.
VERY HIGH CONFIDENCE IN PERIODS/WAVES OF WARM RAINFALL WITH FREEZING
HEIGHTS AT 7.0 KFT AGL AND THE MAXIMUM TEMPERATURES IN THE LOWER
TROPOSPHERE AT 5-6C. HIRES TIME LAGGED ENSEMBLE SYSTEM CONTINUES TO
SUPPORT QPF RANGING BETWEEN 0.25 (NEAR 90% PROBABILITY) AND 0.5 INCH
(APPROXIMATELY 35% PROBABILITY). NON QUARTILE MAPPING DATA OUT OF
THE NBM HAS QPF RANGING BETWEEN 0.30-0.50 INCH. VERY BAGGY
ORGANIZATION OF THE MSLP IMMEDIATELY AROUND THE FIRST FRONT SHIFT
SUGGESTS A VERY MUTED WIND RESPONSE INITIALLY. RIGHT NOW, RAW MODEL
OUTPUT SUGGESTS IT WILL TAKE UNTIL AFTER 12Z FRIDAY TO GET THE TRUE
SURFACE COLD AIR ADVECTION AND BETTER SURFACE WIND RESPONSE.
FAST ZONAL FLOW PATTERN IN PLACE THIS WEEKEND WILL HAVE THE
OPPORTUNITY TO BRING A QUICK HITTING SHORTWAVE/UPPER LEVEL TROUGH
BACK TO MICHIGAN ALREADY SATURDAY AND SUNDAY. CLOSE PROXIMITY OF THE
FEATURE TO THE FORECAST AREA SUGGESTS SOME HIGH DEPENDENCE ON THE
EXACT TRACK. COULD SEE SOME PORTION OF DEFORMATION FORCING OVER THE
AREA THAT DOES BRING IN MORE PRECIPITATION CHANCES. THE CURRENT NBM
DATA IS VERY LEAN/OPTIMISTIC THIS WEEKEND WITH MAINLY DRY WEATHER
AND FAIRLY WARM WEATHER. REFERENCE THE 16.00Z OPERATIONAL ECMWF FOR
A ALTERNATIVE SOLUTION.
MARINE...
WINDS ORGANIZE OUT OF THE SOUTHWEST OVER THE COURSE OF TODAY AS
STRONG LOW PRESSURE TRACKS INTO NORTHERN ONTARIO. WHILE A 50-60KT
LLJ IS SET TO EXPAND ACROSS THE CENTRAL GREAT LAKES BY LATE DAY,
STRONG WARM ADVECTION LIMITS THE DEGREE OF MIXING OVER THE COLDER
LAKE WATERS WHICH IS EXPECTED TO PREVENT GUSTS TO STRONG GALES
(>40KTS). THAT SAID, GRADIENT AND FETCH DIRECTION STILL LIKELY
SUPPORT FREQUENT GUSTS TO 35-40KTS ACROSS THE SAGINAW BAY AND
CENTRAL PORTIONS OF LAKE HURON LATE AFTERNOON INTO TONIGHT WITH GALE
WARNINGS STILL IN EFFECT FOR THESE WATERS. STRONG SOUTHWESTERLY
WINDS WILL ALSO SUPPORT UNSTABLE ICE CONDITIONS IN THE INNER SAGINAW
BAY WITH POTENTIAL FOR FLOES TO BREAK OFF AND DRIFT INTO THE OPEN
WATERS. COLD FRONT THEN GLANCES THE REGION LATE TONIGHT-EARLY
WEDNESDAY MORNING USHERING IN RENEWED NORTHWEST COLD ADVECTION.
THERE REMAINS SOME UNCERTAINTY IN THE STRENGTH OF THESE
NORTHWESTERLY WINDS AS THE CORE OF COLD AIR HOLDS JUST NORTH OF THE
SOO/MANITOULIN ISLAND; HOWEVER, HIGH RES MODELS AND INTERNAL
PROBABILISTIC GUIDANCE CONTINUE TO HIGHLIGHT A 3-5HR WINDOW FOR
GUSTS TO LOWER END GALES ACROSS NORTHERN LAKE HURON. AS SUCH, THERE
IS JUST ENOUGH CONFIDENCE TO EXPAND THE GALE WARNINGS TO COVER THIS
FLOW REGIME. A BRIEF LULL IN WINDS OCCUR WEDNESDAY AS THE NORTHERN
EDGE OF OHIO VALLEY HIGH PRESSURE DRIFTS OVERHEAD BEFORE ANOTHER
STRONG LOW ARRIVES OVER THE NORTHERN GREAT LAKES THURSDAY. THIS
SYSTEM CARRIES A SOLID LIKELIHOOD OF GALES GIVEN THE CLOSER TRACK
(COMPARED TO TODAY'S LOW) AND DEEPER CENTRAL PRESSURE.
DTX WATCHES/WARNINGS/ADVISORIES
MI...NONE.
LAKE HURON...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO NOON EST WEDNESDAY
FOR LHZ442-443.
GALE WARNING FROM 2 AM TO NOON EST WEDNESDAY FOR LHZ361.
GALE WARNING FROM 3 PM THIS AFTERNOON TO NOON EST WEDNESDAY FOR
LHZ362.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 6 AM EST WEDNESDAY FOR
LHZ363-421-422-441-462.
LAKE ST CLAIR...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO NOON EST WEDNESDAY
FOR LCZ460.
MICHIGAN WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO NOON EST WEDNESDAY
FOR LEZ444.
AVIATION.....SF
DISCUSSION...CB
MARINE.......KDK
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